Hi Fresh Opt,
1/ increase the Cell Reselect Offset of the Indoor cell, much above the CRO of outdoor Umbrella cells.
2/ the indoor cell is define as “Micro” or “Indoor” ? then there shouldn’t be any outgoing HO from this indoor to the umbrellas… (it’s automatic)
3/ enable the cause 14 in Umbrellas (already done, probably) (if not, then the parameter name is EN_MCHO_NCELL, or something like this), then tune the adjacency parameter L_RXLEV_CPT_HO(Umbrella, Indoor) to a little lower value : – 77dBm or -80dBm, etc.
The lower you go, the more traffic will be sent to the indoor cell. Don’t go too low 🙂